I loved her for her literate romantic suspense, and then for her Merlin books. From the opening of the NY Times obit:

Mary Stewart, the British author of romantic thrillers who jumped genres in her 50s to create the internationally best-selling trilogy of Merlin books, reimagining the Arthurian legend from a sorcerer’s point of view, died on May 9 at her home in the village of Loch Awe, on the west coast of Scotland. She was 97.